There is a pressing need to build the capacity of communities to follow the guidelines of the American Academy of Pediatrics to screen all children for ASD at 18 and 24 months (Johnson & Myers, 2007) as research indicates that earlier intervention maximizes outcomes. In response to PA-10-158, the overarching purpose of this investigation is to validate the effectiveness of a new automated online version of the Early Screening for Autism and Communication Disorders- the Smart ESAC, that uses smart technology to seamlessly transition from 10 broadband questions about communication delay to 20 autism-specific questions for children who screen positive on the initial broadband screen. The Smart ESAC is designed as a universal screen for communication delays and ASD at 12 and 18 months of age. We will conduct a large-scale longitudinal study of the validity of the Smart ESAC through community primary care providers (PCPs) in the Florida panhandle, which offers small urban and rural healthcare settings and diversity in race, ethnicity, and socioeconomic level. We will also study family engagement in screening and diagnosis to improve health disparities. We will recruit up to 32 PCPs who will implement screening with 8,424 infants at 12 months of age and follow these children longitudinally over the 5 years of this project. We will invite families to participate in diagnostic evaluations for all children who screen positive and randomly selected children with a negative screen to detect about 842 children with communication delays and about 84 children with ASD. This longitudinal study will address the following specific aims: Aim 1. To study the established cutoff points and estimate sensitivity, specificity, and discrimination for the Smart ESAC at 12 and 18 months in predicting communication delay or red flags for autism at 12 and 18 months, and in predicting distally a best-estimate diagnosis of ASD at 18-24 and 30-36 months; Aim 2. To study individual items and underlying dimensions of the constructs measured by the Smart ESAC using factor analysis and item response theory to determine the number of factors and differential item function within factors, to ultimately predict diagnostic outcome; and Aim 3. To identify barriers in community settings that impede the screening and referral process and culturally sensitive strategies that function to improve this process. The expected outcomes of the proposed research will have a significant impact on early detection of communication disorders and ASD through documentation of the accuracy of a new promising universal automated screening tool for infants and toddlers. This study will also impact family engagement in community screening processes through the development of a manualized engagement intervention based on Motivational Interviewing and family-centered strategies. Findings will also contribute one of the largest and youngest samples of infants and toddlers identified in primary care, with the potential of lowering the age to screen for communication delay and ASD to 12 months, which will have important implications for earlier access to intervention and immediate implementation in community settings.